Valid Arc Lost 2

I spoke to soon....

So I did about 5 x 50mm test cuts, no worries.

Went to cut some code and my very first pierce “valid arc lost”

So close.

Okay an interesting finding,

I went back to the run tab and completed another 4 x 70mm cuts no worries

Then on the 5th one it pierced and started cutting, then after about 40mm it stopped and threw up the arc error again.

I’m not sure what this points to?

It could point to there is more oxide to blow away yet.
It could also mean you are cutting too fast or too high... Try reducing your feed rate by 20%. Then try - 10%

I think Plasmac now has a setting that ignores ArcoK for cutting expanded metal. I would enable that and pause the cut if you don't cut right through.

My thinking is that if you are loosing and ArcOK because of an intermittent fault on a relay, it should cut fine without ArcOK becasue the plasma cutter is happy.

But before you do that, we need to eliminate cut height and cut speed as being the cause by trial and error.

Anyway, its great the resistors improved your results. You have to have a working circuit before debounce can help at all. I feel your pain as it brings back memories...

Okay so after taking in all the advice listed above, I think i'm almost there!

So working through tommy's list this is what I did.

Firstly, I turned down the amps on the everlast plasma cutter from 42 amps to 35 and slowed down my cut feedrate. I thought this might help with power fluctuations.

Secondly, I went out and got another good 2 stage air filter, giving me 4 in total now. I am also toying with the idea of adding my own homemade wall mounted desiccant filter, does anyone have any experience or recommendations with this?

Thirdly, I double checked every wire to see if there were any broken wires.

Next I played around with the cut speed and I ended up dropping it about 40% (seems large but I also dropped the amps too)

After all this, and Rod's new arc ok resistor resistor blowing away the built up oxide, I am getting reliable cuts with about 30 minutes of cut time not throwing up a single error yet.

Thanks for all your help guys and fingers crossed I dont have to reply to this topic again!

Great teamwork Sparky! Thanks for the update.

Hello all,
I just came across this thread, and didnt wanted to open a new one.

I have a simple ebay plasma cutter and 2 different machine torches. My Plasma cutter has no communication with PlasmaC or any machine periphery whatsoever. Even the Arc OK is "bridged" so its constantly "OK". While cutting the same part using torch 1, it goes trough without any trouble, using torch 2, with the same gcode, i get multible valid arc lost errors. Does someone has an explanation for that? Also on torch 2 you can observe the arc lost, the torch is sputtering and then the program stops due to the error. But my question is how can plasma C sense that without any imput data from the plasma? Also its not the gcode since it works on torch 1 and not on torch 2 psychic?